1. Field of the Invention
The present invention relates to a method for measuring smoking topography.
2. Description of the Related Art
Tobacco use, particularly cigarette smoking, is the leading cause of preventable illness and death in the United States. Despite the availability of pharmacotherapies for tobacco dependence, each year more than 400,000 Americans die too young because of smoking-related diseases. Nearly, one in four U.S. Adults and one in three teenagers smoke. Tragically, if current trends continue, an estimated 25 million people (including 5 million of today's children) will die prematurely of smoking-related disease. Cigarette smoking costs an estimated 419,000 American lives and $100 billion in direct and indirect health care expenses annually (Center for Disease Control 1994).
As indicated in the Surgeon General's Report titled “Reducing Tobacco Use” published in the year 2000, tobacco dependence is currently viewed as a chronic disease with remission and relapse. Although interventions do provide some cessation from smoking, achieving long-term abstinence from smoking has been extremely difficult for smokers. There is little understanding of how various treatments produce therapeutic effects. Since the overall success in improving the public health depends upon a dramatic reduction in the rate of tobacco use, clinical researchers require state-of-the-art tools that will help identify factors that change smoking behavior. Tools that provide detailed measurements of smokers' puffing behavior have long been a mainstay in successful smoking research programs, and they continue to help clinical researchers understand the factors that influence tobacco use in the laboratory. Smoking topography or puff topography refers to the measures that assess puffing behavior.
Measurement of smoking topography variables such as puff volume, puff duration, inter-puff interval, peak flow, and the number of puffs by a smoker has been central to the study of smoking behavior. Smoking topography measurement has demonstrated that nicotine self-administration helps to drive tobacco use, and has predicted in the laboratory, the efficacy of nicotine replacement medications. Additionally, the sensitivity gained by puff topography measurement has uncovered factors that change cigarette use, including personality type, gender, time of day, and smoke dilution through filter ventilation holes. Smoking topography may be critical in the assessment of nicotine dependence in smokers. Thus, the ability to measure smoking topography is likely essential to comprehensive research programs tasked to understand and treat smoking behavior.
In the prior art, smoking topography measurement devices used a cigarette holder or mouthpiece that acts as a flowmeter to capture pressure differences as smoke is inhaled through the holder. A pressure sensor converts pressure to voltage, which is then converted to flow rate using calibrated computer software. While highly effective in a laboratory setting, these smoking topography devices share the disadvantage of relying on locally made hardware and software. Therefore, Plowshare® Technologies, Inc. developed the Clinical Research Support System (CReSS). This desktop system, based on well-tested measurement techniques, used an integrated Windows® platform that automates data collection in smoking topography. The primary components of the CReSS are a personal computer 1 running a Windows® operating system, a mouthpiece 3 holding a cigarette, and a measurement interface unit 2 connected to the personal computer 1 and mouthpiece 3 as shown in FIG. 1. CReSS assesses puffing behavior using a differential pressure flow meter contained in a plastic mouthpiece 1 tethered by vinyl tubing to a measurement interface unit 2. By measuring differential pressure at the two precisely placed taps in the mouthpiece 3, CReSS accurately calculates flow rate during each smoking inhalation. The relationship between differential pressure and flow rate is given by a power equation based on the respective diameters of the flow meter components and location of the pressure taps. When precise timing is correlated with instantaneous measured flow, smoking topographical information can be derived including: puff volume, puff duration, puff number, inter-puff interval (time between the end of one puff and the beginning of the next puff), and peak puff flow rate (highest sampled flow rate).
Although CReSS as a desktop or laptop measurement system provides smoking topographical information in a clinical laboratory setting, CReSS can not be used for smoking topography measurements outside of the intended clinical laboratory setting. It is simply impractical for a smoker to carry a personal computer 1, measurement interface unit 2, and a tethered mouthpiece 3 for ambulatory measurement during a smoker's daily routine. Therefore, CReSS is impractical for natural smoking topography measurements while a smoker is in his or her normal everyday environment.
Naturalistic observation of a smoker is very important in smoking research because the smoker's environment may influence smoking behavior. Some factors that modulate or change smoking behavior are environment-specific. These factors include the proximity of other smokers, the influence of smoking and non-smoking peers, and the availability of other reinforcing activities that are incompatible with smoking, such as physical activity. The relative influence of these factors may be studied most optimally in the natural environment, provided that adequate smoking topography measurement equipment is available. Studying cigarette behavior in the natural environment will be essential to understanding the etiology of tobacco dependence—why people alter their tobacco use patterns from first use, to occasional use, to eventual regular, daily use. Therefore, there is a need for providing a truly portable smoking topography measurement device or system capable of accurately measuring smoking topography wherever a smoker chooses to smoke. Moreover, there is a similar need for a smoking topography measurement device capable of measuring any substance, which can be inhaled through the mouth including other drugs such as marijuana.